Association between inflammatory bowel disease and prostate cancer: A large‐scale, prospective, population‐based study

Inflammatory bowel disease (IBD) is an established risk factor for colorectal cancer. Recent reports suggesting IBD is also a risk factor for prostate cancer (PC) require further investigation. We studied 218 084 men in the population‐based UK Biobank cohort, aged 40 to 69 at study entry between 2006 and 2010, with follow‐up through mid‐2015. We assessed the association between IBD and subsequent PC using multivariable Cox regression analyses, adjusting for age at assessment, ethnic group, UK region, smoking status, alcohol drinking frequency, body mass index, Townsend Deprivation Index, family history of PC and previous prostate‐specific antigen testing. Mean age at study entry was 56 years, 94% of the men were white, and 1.1% (n = 2311) had a diagnosis of IBD. After a median follow‐up of 78 months, men with IBD had an increased risk of PC (adjusted hazard ratio [aHR] = 1.31, 95% confidence interval [CI] = 1.03‐1.67, P = .029). The association with PC was only among men with the ulcerative colitis (UC; aHR = 1.47, 95% CI = 1.11‐1.95, P = .0070), and not Crohn's disease (aHR 1.06, 95% CI = 0.63‐1.80, P = .82). Results are limited by lack of data on frequency of health care interactions. In a large‐scale, prospective cohort study, we detected an association between IBD, and UC specifically, with incident PC diagnosis. What's new? Inflammatory bowel disease (IBD) is associated with colorectal cancer risk, but what about prostate cancer? Some reports suggest there could be a link. IBD is characterized by chronic debilitating inflammation, and includes Crohn's disease and ulcerative colitis. Here, the authors studied the association between IBD and prostate cancer in 218 084 men from the UK Biobank cohort, where prostate cancer screening is not widespread. They found that men with ulcerative colitis specifically had an increased risk of prostate cancer. Further work is warranted to confirm the association, but incorporating IBD status into cancer screening protocols could be worth considering.